A new transmission methodology for quality assurance in radiotherapy based on radiochromic film measurements.

Despite individual quality assurance (QA) being recommended for complex techniques in radiotherapy (RT) treatment, the possibility of errors in dose delivery during therapeutic application has been verified. Therefore, it is fundamentally important to conduct in vivo QA during treatment. This work presents an in vivo transmission quality control methodology, using radiochromic film (RCF) coupled to the linear accelerator (linac) accessory holder. This QA methodology compares the dose distribution measured by the film in the linac accessory holder with the dose distribution expected by the treatment planning software. The calculated dose distribution is obtained in the coronal and central plane of a phantom with the same dimensions of the acrylic support used for positioning the film but in a source-to-detector distance (SDD) of 100 cm, as a result of transferring the IMRT plan in question with all the fields positioned with the gantry vertically, that is, perpendicular to the phantom. To validate this procedure, first of all a Monte Carlo simulation using PENELOPE code was done to evaluate the differences between the dose distributions measured by the film in a SDD of 56.8 cm and 100 cm. After that, several simple dose distribution tests were evaluated using the proposed methodology, and finally a study using IMRT treatments was done. In the Monte Carlo simulation, the mean percentage of points approved in the gamma function comparing the dose distribution acquired in the two SDDs were 99.92% ± 0.14%. In the simple dose distribution tests, the mean percentage of points approved in the gamma function were 99.85% ± 0.26% and the mean percentage differences in the normalization point doses were -1.41%. The transmission methodology was approved in 24 of 25 IMRT test irradiations. Based on these results, it can be concluded that the proposed methodology using RCFs can be applied for in vivo QA in RT treatments.

Surgical correction of pulmonary artery aneurysm with extrinsic compression of the left main coronary artery: A case report.

Pulmonary artery aneurysm (PAA) is a rare disease, with a poorly known natural history, complex diagnosis and may evolve with serious complications, such as compression of adjacent anatomical structures. In some cases, the presence of such complications is what determines the symptoms and is the initial manifestation of the disease. This paper aims to report the case of a patient with typical angina, submitted to cardiac catheterization, which showed, among other lesions, severe left main coronary lesion with characteristics that led to the suspicion of extrinsic compression, which was identified as caused by a PAA. The treatment chosen in this case was surgical, reported concurrently with a literature review that guided the medical team in their decision-making. RELEVANCE FOR PATIENTS: Surgical correction of PAA may provide resolution of coronary symptoms in affected individuals.

Seroepidemiology of chronic hepatitis B and C in the French Caribbean Island of Guadeloupe.

BACKGROUND: The prevalence of chronic hepatitis B and C was evaluated some twenty years ago among specific populations in Guadeloupe. The present study was designed to update these data and determine epidemiological features of chronic hepatitis B and C infections in the French Caribbean island of Guadeloupe. FINDINGS: The present study was carried out at the Sainte Genevieve Health and Prevention Center (Guadeloupe), between May 2006 and July 2007. This is a medical center where patients can attend a free medical check-up paid for by the Social Security system. Data on hepatitis B (HBV) and C (HCV) status and epidemiological factors were collected for this study.A total of 2,200 patients were included in the study. The prevalence of HBV surface antigen was 1.41% (95% CI: 1.0-2.0), and 0.55% (95% CI: 0.28-0.96) for HCV. The vaccination rate against HBV was 42.0%. HBV transmission was associated with piercing (12.9%, p = 0.014) and familial exposure (6.4%, p < 0.001) and HCV transmission with gynecological surgery (50.0%, p = 0.01). The HBV profile was generally hepatitis B e antigen-negative (94.5%). No hepatitis delta was found. For HCV, genotype 1 was predominant (80%). CONCLUSIONS: This is the first study on the prevalence of HBV and HCV among a general clinic based population in Guadeloupe and the Caribbean islands. This study reveals that Guadeloupe is an area of low endemicity for HBV and low HCV prevalence. The reasons for these low prevalence rates are mainly related to the vaccination campaigns carried out during the past twenty years for HBV and the decrease of nosocomial transmission for HCV.